Fluid injection devices, notably needle syringes, and particularly automated devices of these types have gained wide acceptance over the past few decades by industry, and by the medical and scientific communities generally, for use in dispensing small accurately measured quantities of fluid specimens into analytical instruments. A large measure of this success is due to the automation feature, and modern data gathering techniques, which greatly reduce operating manpower without decrease in accuracy. There remains a considerable demand for improved automated devices of these types.
Typically, an automatic fluid injector is constituted of three major sub-assemblies, viz., (a) a syringe, inclusive of a barrel and needle dispensing element which is employed to measure out and convey a fluid specimen directly to the inlet of an analytical instrument, (2) an injector feed assembly for transfer of a fluid specimen from a supply source to the barrel of the syringe, and (3) a magazine into which fluid specimen filled vials are loaded for pick up by the injector feed assembly for transfer to the barrel of the syringe. The syringe, in particular includes a barrel into which a fluid specimen can be loaded, a needle mounted on an end of the barrel, and means for the displacement of the fluid specimen from said barrel via the dispensing end of the needle into said inlet. Typically the displacement means is a plunger which traverses the length of the barrel. Or, the displacement means can be a valve which after passage of the fluid specimen into the barrel can be closed, and thereafter the fluid specimen can be displaced from the barrel by transport of an end of the needle into the barrel to express a fluid specimen from the opposite dispensing end of the needle. The injector feed assembly typically is constituted of a probe sub-assembly inclusive of a pair of concentrically mounted hollow needles, an end of which can be projected into a septum sealed fluid-specimen containing vial for the pick up of said fluid specimen for filling the barrel of said syringe. The probe sub-assembly is separately movably mounted adjacent the syringe, and transfer lines are employed to convey fluid specimens to the barrel of the syringe when the vial is pressurized with a gas to transport the fluid specimen via one of the pair of hollow needles. The magazine transports the fluid specimen-containing septum sealed vials in seratim to a position for pick up by the pair of hollow needles of said probe sub-assembly for delivery to the barrel of said syringe via thrust of the probe through the septum of a vial so that the contents of the vial can be pressurized by delivery of gas from a source through a first flow path provided by the pair of needles of said probe sub-assembly to produce flow of fluid specimen from the vial through a second flow path provided by the pair of needles of the probe sub-assembly to the barrel of the syringe. Such instruments are described, e.g., by reference to U.S. Pat. No. 3,754,443; U.S. Pat. No. 3,824,859; U.S. Pat. No. 3,885,438; U.S. Pat. No. 3,940,995; U.S. Pat. No. 4,000,654 and U.S. Pat. No. 4,044,616. Wherein these instruments have served admirably, there exists an incentive to further simplify the construction of these instruments, as well as to further provide novel instruments for general and specifically defined usages.